Looks like western writing. I don’t think that dirt-floor, sparking-wires sweatshop workers print English that way.
The writer is not a factory worker.
The writer is an inmate of a Lao Gai, a “Reform Through Labor” concentration camp.
There are almost 7 million inmate, most are being held for political or religious crimes.
It is not difficult to imagine the writer is a priest or a pastor who learned English by studying the Bible.
I don’t buy it at all. The woman works for Goodwill and may think that this would help bring the plight of the sweatshop workers in China to the forefront. I am not against it being brought up, but I sincerely doubt this letter came from one of their workers. I realize there would be many bilinguals in China, but the penmanship and so on seems pretty advanced and Americanized. I very well may be wrong. JMHO